A Chronic, Conscious Large Animal Platform to Quantify Therapeutic Effects of Sacral Neuromodulation on Bladder Function

PurposeSacral neuromodulation is a Food and Drug Administration approved therapy for urinary urge incontinence, urgency-frequency and fecal incontinence. Most preclinical studies have used anesthetized preparations in small animals. To expand the testing capabilities of sacral neuromodulation stimulation parameters and novel concepts we created a large animal model in fully conscious sheep.Materials and MethodsSix adult female sheep were tested weekly using 10 trials of single fill cystometry, similar to clinical urodynamics. Maximal bladder capacity was measured without (trials 1 to 5) and with (trials 6 to 10) sacral neuromodulation. A mixed effects regression model was used to analyze the effect of sacral neuromodulation on bladder capacity.ResultsAcute sacral neuromodulation significantly increased bladder capacity in conscious female sheep from 75.2 to 118.7 ml, an almost 60% increase. This was not simply an effect of repeat cystometric trials since testing without sacral neuromodulation was not associated with an increase in bladder capacity.ConclusionsThese data demonstrate the effects of acute sacral neuromodulation on bladder capacity in the conscious sheep. This model represents a useful testing platform for novel sacral neuromodulation concepts such as alternate methods and parameters of therapy delivery.